lima-vm/lima · error

failed to run : ; stderr=%#q

Error message

failed to run %v: %w; stderr=%#q

What it means

startAndStreamKubectl launches a long-running kubectl command with StdoutPipe and streams its output; if cmd.Start fails (or the subsequent cmd.Wait fails, which is wrapped with the same message), this error includes cmd.Args and whatever stderr was captured. Note that stderr is captured into a buffer that is only filled during the run, so on Start failure it is typically empty.

Solutions

1. Check that the kubectl binary in cmd.Args exists and is executable inside the guest.
2. Inspect the stderr=... portion (on Wait failures) for kubectl's own error output.
3. Verify the kubeconfig remains valid for the duration of streaming (`kubectl auth can-i get services`).
4. If the error appears during instance shutdown, it is expected context cancellation and can be ignored.

Example fix

// before
exec.Command("kubectl-not-installed", "get", "services", "--watch")
// after
exec.Command("kubectl", "get", "services", "--watch") // ensure kubectl is on PATH

if _, err := exec.LookPath("kubectl"); err != nil {
    return fmt.Errorf("kubectl not found in PATH")
}
if _, err := os.Stat(kubeconfig); err != nil {
    return fmt.Errorf("kubeconfig missing: %w", err)
}

if err := startAndStreamKubectl(cmd); err != nil {
    if errors.Is(err, exec.ErrNotFound) || strings.Contains(err.Error(), "not found") {
        log.Println("install kubectl in the guest")
    } else if errors.Is(err, context.Canceled) {
        // expected during shutdown; ignore
    }
}

When it happens

Trigger: The streaming kubectl command cannot be started: the kubectl binary is missing or not executable (exec: not found / permission denied), or the process exits during Wait with a nonzero status (context canceled, auth failure, connection loss) - the Wait variant wraps the same message.

Common situations: kubectl absent from PATH in the guest; kubeconfig removed or made invalid while streaming; cluster API server restarting mid-stream; guestagent context canceled during shutdown (benign during teardown).

Related errors

• failed to run : expected `yes`, got %#q
• failed to run : ; stdout=%#q, stderr=%#q
• failed to scan kubectl event stream
• failed to unmarshal line %#q
• failed to unmarshal service object

AI-assisted analysis of lima-vm/lima@dd909d0973 (2026-09-01). Data as JSON: /api/errors/6d8770f8e6694957. Report an issue: GitHub.

Appendix: source

Thrown at pkg/guestagent/kubernetesservice/kubernetesservice.go:136

		return fmt.Errorf("failed to run %v: %w; stdout=%#q, stderr=%#q", cmd.Args, err, stdout.String(), stderr.String())
	}
	if strings.TrimSpace(stdout.String()) != "yes" {
		return fmt.Errorf("failed to run %v: expected `yes`, got %#q", cmd.Args, stdout.String())
	}
	return nil
}

func (s *ServiceWatcher) startAndStreamKubectl(cmd *exec.Cmd) error {
	stdout, err := cmd.StdoutPipe()
	if err != nil {
		return err
	}

	var stderr bytes.Buffer
	cmd.Stderr = &stderr

	if err := cmd.Start(); err != nil {
		return fmt.Errorf("failed to run %v: %w; stderr=%#q", cmd.Args, err, stderr.String())
	}

	readErr := s.readKubectlStream(stdout)
	waitErr := cmd.Wait()
	if waitErr != nil {
		waitErr = fmt.Errorf("failed to run %v: %w; stderr=%#q", cmd.Args, waitErr, stderr.String())
	}
	return errors.Join(readErr, waitErr)
}

// readKubectlStream reads kubectl JSON watch events from r and updates the internal
// services map. The stream is newline-delimited JSON objects representing "WatchEvent".
func (s *ServiceWatcher) readKubectlStream(r io.Reader) error {
	scanner := bufio.NewScanner(r)
	// increase buffer in case of large JSON objects
	const maxBuf = 10 * units.MiB
	buf := make([]byte, 0, 64*units.KiB)
	scanner.Buffer(buf, maxBuf)

View on GitHub (pinned to dd909d0973)